The combined rate of all video and audio elementary stream packets common to one program. This rate also includes the VBI and sub-picture private stream data, which MPEG treats as a private stream type.

The combined rate of all video and audio elementary stream packets common to one program. This rate also includes the VBI and sub-picture private stream data, which MPEG treats as a private stream type.

Name of application to connect on the RTMP server. This option overrides the parameter specified in the URI.

rtmp_buffer

string

Set the client buffer time in milliseconds. The default is 3000.

rtmp_flashver

string

Version of the Flash plugin used to run the SWF player. The default is LNX 9,0,124,2. (When publishing, the default is FMLE/3.0 (compatible; 'libavformat version').

rtmp_live

string

Specify that the media is a live stream. No resuming or seeking in live streams is possible. The default value is any, which means the subscriber first tries to play the live stream specified in the playpath. If a live stream of that name is not found, it plays the recorded stream. The other possible values are live and recorded.

rtmp_pageurl

string

URL of the web page in which the media was embedded. By default no value will be sent.

rtmp_playpath

string

Stream identifier to play or to publish. This option overrides the parameter specified in the URI.

rtmp_subscribe

string

Name of live stream to subscribe to. By default no value will be sent. It is only sent if the option is specified or if rtmp_live is set to live.

The combined rate of all video and audio elementary stream packets common to one program. This rate also includes the VBI and sub-picture private stream data, which MPEG treats as a private stream type.

Sets the passphrase for encryption. This turns encryption on on this side (or turns it off, if empty passphrase is passed).

mss

int

1500

Maximum Segment Size. Used for buffer allocation and rate calculation using packet counter assuming fully filled packets. The smallest MSS between the peers is used. This is 1500 by default in the overall internet. This is the maximum size of the UDP packet and can be only decreased, unless you have some unusual dedicated network settings. Not to be mistaken with the size of the UDP payload or SRT payload — this size is the size of the IP packet, including the UDP and SRT headers.

fc

int

25600

Flight Flag Size (maximum number of bytes that can be sent without being acknowledged).

Sender nominal input rate. Used along with OHEADBW, when MAXBW is set to relative (0), to calculate maximum sending rate when recovery packets are sent along with main media stream (INPUTBW × (100 + OHEADBW) / 100). If INPUTBW is not set while MAXBW is set to relative (0), the actual input rate is evaluated inside the library.

This flag sets both SRTO_RCVLATENCY and SRTO_PEERLATENCY to the same value. Note that prior to version 1.3.0 this is the only flag to set the latency, however this is effectively equivalent to setting SRTO_PEERLATENCY, when the side is sender (see SRTO_SENDER) and SRTO_RCVLATENCY when the side is receiver, and the bidirectional stream sending in version 1.2.0is not supported.

tsbpddelay

tlpktdrop

bool

true

Too-late Packet Drop. When enabled on receiver, it skips missing packets that have not been delivered in time and delivers the subsequent packets to the application when their time-to-play has come. It also sends a fake ACK to the sender. When enabled on sender and enabled on the receiving peer, sender drops the older packets that have no chance to be delivered in time. It is automatically enabled in sender if receiver supports it.

snddropdelay

nakreport

bool

true

When set to true, Receiver will send UMSG_LOSSREPORT messages periodically until the lost packet is retransmitted or intentionally dropped

conntimeo

int

3000

Connect timeout. SRT cannot connect for RTT > 1500 msec (2 handshake exchanges) with the default connect timeout of 3 seconds. This option applies to the caller and rendezvous connection modes. The connect timeout is 10 times the value set for the rendezvous mode (which can be used as a workaround for this connection problem with earlier versions)

lossmaxttl

int

0

The value up to which the Reorder Tolerance may grow. When Reorder Tolerance is > 0, then packet loss report is delayed until that number of packets come in. Reorder Tolerance increases every time a "belated" packet has come, but it wasn't due to retransmission (that is, when UDP packets tend to come out of order), with the difference between the latest sequence and this packet's sequence, and not more than the value of this option. By default it's 0, which means that this mechanism is turned off, and the loss report is always sent immediately upon experiencing a "gap" in sequences.

rcvlatency

int

0

The time that should elapse since the moment when the packet was sent and the moment when it's delivered to the receiver application in the receiving function. This time should be a buffer time large enough to cover the time spent for sending, unexpectedly extended RTT time, and the time needed to retransmit the lost UDP packet. The effective latency value will be the maximum of this options' value and the value of SRTO_PEERLATENCY set by the peer side.

peerlatency

int

0

The latency value (as described in SRTO_RCVLATENCY) that is set by the sender side as a minimum value for the receiver.

minversion

int

0

The minimum SRT version that is required from the peer. A connection to a peer that does not satisfy the minimum version requirement will be rejected.

streamid

string

A string limited to 512 characters that can be set on the socket prior to connecting. This stream ID will be able to be retrieved by the listener side from the socket that is returned from srt_accept and was connected by a socket with that set stream ID. SRT does not enforce any special interpretation of the contents of this string. As this uses internally the std::string type, there are additional functions for it in the legacy/C++ API (udt.h): UDT::setstreamid and UDT::getstreamid. This option doesn’t make sense in Rendezvous connection; the result might be that simply one side will override the value from the other side and it’s the matter of luck which one would win

smoother

option_fixed

live

The type of Smoother used for the transmission for that socket, which is responsible for the transmission and congestion control. The Smoother type must be exactly the same on both connecting parties, otherwise the connection is rejected.

messageapi

bool

true

When set, this socket uses the Message API[*], otherwise it uses Buffer API. Note that in live mode (see SRTO_TRANSTYPE option) there’s only message API available.

payloadsize

int

1316

Sets the maximum declared size of a single call to sending function in Live mode. Use 0 if this value isn't used (which is default in file mode). This value shall not be exceeded for a single data sending instruction in Live mode/ Range: up to MTUsize-28-16, usually 1456

transtype

Sets the transmission type for the socket, in particular, setting this option sets multiple other parameters to their default values as required for a particular transmission type. Type: enum. Default: SRTT_LIVE. Range: SRTT_FILE

Sets the passphrase for encryption. This turns encryption on on this side (or turns it off, if empty passphrase is passed).

mss

int

1500

Maximum Segment Size. Used for buffer allocation and rate calculation using packet counter assuming fully filled packets. The smallest MSS between the peers is used. This is 1500 by default in the overall internet. This is the maximum size of the UDP packet and can be only decreased, unless you have some unusual dedicated network settings. Not to be mistaken with the size of the UDP payload or SRT payload — this size is the size of the IP packet, including the UDP and SRT headers.

fc

int

25600

Flight Flag Size (maximum number of bytes that can be sent without being acknowledged).

Sender nominal input rate. Used along with OHEADBW, when MAXBW is set to relative (0), to calculate maximum sending rate when recovery packets are sent along with main media stream (INPUTBW × (100 + OHEADBW) / 100). If INPUTBW is not set while MAXBW is set to relative (0), the actual input rate is evaluated inside the library.

This flag sets both SRTO_RCVLATENCY and SRTO_PEERLATENCY to the same value. Note that prior to version 1.3.0 this is the only flag to set the latency, however this is effectively equivalent to setting SRTO_PEERLATENCY, when the side is sender (see SRTO_SENDER) and SRTO_RCVLATENCY when the side is receiver, and the bidirectional stream sending in version 1.2.0is not supported.

tsbpddelay

tlpktdrop

bool

true

Too-late Packet Drop. When enabled on receiver, it skips missing packets that have not been delivered in time and delivers the subsequent packets to the application when their time-to-play has come. It also sends a fake ACK to the sender. When enabled on sender and enabled on the receiving peer, sender drops the older packets that have no chance to be delivered in time. It is automatically enabled in sender if receiver supports it.

snddropdelay

nakreport

bool

true

When set to true, Receiver will send UMSG_LOSSREPORT messages periodically until the lost packet is retransmitted or intentionally dropped

conntimeo

int

3000

Connect timeout. SRT cannot connect for RTT > 1500 msec (2 handshake exchanges) with the default connect timeout of 3 seconds. This option applies to the caller and rendezvous connection modes. The connect timeout is 10 times the value set for the rendezvous mode (which can be used as a workaround for this connection problem with earlier versions)

lossmaxttl

int

0

The value up to which the Reorder Tolerance may grow. When Reorder Tolerance is > 0, then packet loss report is delayed until that number of packets come in. Reorder Tolerance increases every time a "belated" packet has come, but it wasn't due to retransmission (that is, when UDP packets tend to come out of order), with the difference between the latest sequence and this packet's sequence, and not more than the value of this option. By default it's 0, which means that this mechanism is turned off, and the loss report is always sent immediately upon experiencing a "gap" in sequences.

rcvlatency

int

0

The time that should elapse since the moment when the packet was sent and the moment when it's delivered to the receiver application in the receiving function. This time should be a buffer time large enough to cover the time spent for sending, unexpectedly extended RTT time, and the time needed to retransmit the lost UDP packet. The effective latency value will be the maximum of this options' value and the value of SRTO_PEERLATENCY set by the peer side.

peerlatency

int

0

The latency value (as described in SRTO_RCVLATENCY) that is set by the sender side as a minimum value for the receiver.

minversion

int

0

The minimum SRT version that is required from the peer. A connection to a peer that does not satisfy the minimum version requirement will be rejected.

streamid

string

A string limited to 512 characters that can be set on the socket prior to connecting. This stream ID will be able to be retrieved by the listener side from the socket that is returned from srt_accept and was connected by a socket with that set stream ID. SRT does not enforce any special interpretation of the contents of this string. As this uses internally the std::string type, there are additional functions for it in the legacy/C++ API (udt.h): UDT::setstreamid and UDT::getstreamid. This option doesn’t make sense in Rendezvous connection; the result might be that simply one side will override the value from the other side and it’s the matter of luck which one would win

smoother

option_fixed

live

The type of Smoother used for the transmission for that socket, which is responsible for the transmission and congestion control. The Smoother type must be exactly the same on both connecting parties, otherwise the connection is rejected.

messageapi

bool

true

When set, this socket uses the Message API[*], otherwise it uses Buffer API. Note that in live mode (see SRTO_TRANSTYPE option) there’s only message API available.

payloadsize

int

1316

Sets the maximum declared size of a single call to sending function in Live mode. Use 0 if this value isn't used (which is default in file mode). This value shall not be exceeded for a single data sending instruction in Live mode/ Range: up to MTUsize-28-16, usually 1456

transtype

Sets the transmission type for the socket, in particular, setting this option sets multiple other parameters to their default values as required for a particular transmission type. Type: enum. Default: SRTT_LIVE. Range: SRTT_FILE

kmrefreshrate

kmpreannounce

split_channels

option_fixed

0

Split audio channels

embed_cc

bool

false

Enable embedding Closed Captions (ATSC) into elementary video stream

embed_scte35

bool

false

Enable embedding SCTE-35 triggers into MPEG transport stream

service_name

string

MPService001

Set Service Name

service_provider

string

Medialooks MPlatform 1.7

Set Service Provider

transport_stream_id

int

1

Set transport_stream_id field.

original_network_id

int

1

Set original_network_id field.

muxrate

int

1

The combined rate of all video and audio elementary stream packets common to one program. This rate also includes the VBI and sub-picture private stream data, which MPEG treats as a private stream type.

(Uncompressed) PCM signed 32-bit little-endian

ADPCM IMA QuickTime

ADPCM Microsoft

MP3 Lame (MPEG audio layer 3)

Configuration Parameter: libmp3lame

Video Codecs

General Video Attributes

used when no other attributes are specified

Name

Type

Default

Description

b

int

5M

Set bitrate (in bits/s)

bt

int

4000000

Set video bitrate tolerance (in bits/s). In 1-pass mode, bitrate tolerance specifies how far ratecontrol is willing to deviate from the target average bitrate value. This is not related to min/max bitrate. Lowering tolerance too much has an adverse effect on quality.

flags

flags

ildct - use interlaced dct

low_delay - force low delay

ilme - interlaced motion estimation

cgop - closed GOP

size

string

Resolution of video. Format: WIDTHxHEIGHT.

ar

option

Aspect ratio of video.

ar_type

option_fixed

Type of video's aspect ratio.

g

int

-1

Keyframe interval, also known as GOP length. This determines the maximum distance between I-frames. Very high GOP lengths will result in slightly more efficient compression, but will make seeking in the video somewhat more difficult.

This parameter simply serves to limit the max number of B-frames. Note that Baseline Profile, such as that used by iPods, does not support B-frames. Recommended default: 16

b_strategy

int

0

Strategy to choose between I/P/B-frames. 0: Very fast; 1: Fast, a good balance between speed and quality; 2: A much slower but more accurate B-frame decision mode that correctly detects fades and generally gives considerably better quality.

maxrate

int

0

Specifies the maximum bitrate at any point in the video. Requires the VBV buffersize to be set. This option is generally used when encoding for a piece of hardware with bitrate limitations.

minrate

int

0

Set min bitrate tolerance (in bits/s). Most useful in setting up a CBR encode. It is of little use elsewise.

bufsize

int

0

Set ratecontrol buffer size (in bits). Depends on the profile level of the video being encoded. Set only if you're encoding for a hardware device.

i_qfactor

double

-0.800000

Qscale difference between I-frames and P-frames.

dct

option_fixed

auto

DCT algorithm

auto - autoselect a good one (default)

fastint - fast integer

int - accurate integer

mmx - MMX

altivec - altivec

faan - floating point AAN DCT

aspect

double

0/1

Sample aspect ratio

cmp

option_fixed

sad

Full pel motion estimation compare function

cmp_func

sse - sum of squared errors

satd - sum of absolute Hadamard transformed differences

dct - sum of absolute DCT transformed differences

bit - number of bits needed for the block

rd - rate distortion optimal, slow

zero - 0

vsad - sum of absolute vertical differences

vsse - sum of squared vertical differences

nsse - noise preserving sum of squared differences

w53 - 5/3 wavelet, only used in snow

w97 - 9/7 wavelet, only used in snow

dctmax - DCT max

chroma - Chroma

subq

int

8

Sub pel motion estimation quality

me_range

int

0

MErange controls the max range of the motion search.

coder

option_fixed

vlc

ac - arithmetic coder

raw - raw (no encoding)

rle - run-length coder

deflate - deflate-based coder

sc_threshold

int

0

Adjusts the sensitivity of codec's scenecut detection.

lmin

int

236

Min lagrange factor (VBR)

lmax

int

3658

Max lagrange factor (VBR)

rc_init_occupancy

int

0

Number of bits which should be loaded into the rc buffer before decoding starts

threads

option_fixed

detect a good number of threads

dc

int

0

Intra DC Precision indicates the number of bits for quantized DC coefficients of intra-coded blocks; it takes one of the values of 8, 9, 10, or 11 bits. The more bits are used, the more precise quantization is achieved.

profile

option_fixed

unknown

Profile of attributes

tag

string

Codec's tag (for example, 'xvid')

scaling_quality

string

auto

scaling quality for video encoding

refs

int

1

Reference frames to consider for motion compensation

trellis

int

0

0: disabled; 1: enabled only on the final encode of a MB; 2: enabled on all mode decisions. The main decision made in quantization is which coefficients to round up and which to round down. Trellis chooses the optimal rounding choices for the maximum rate-distortion score, to maximize PSNR relative to bitrate.

NVIDIA NVEnc H.264 Encoder

The average bit rate in bps is the target bit rate used for rate control

g

int

15

This is the IDR period

bf

int

1

This sets the distance of one P picture from the previous P picture. e.g. for IBBPBBP, set the value as 3

rc_type

option_fixed

Auto

The rate control type

preset

option_fixed

Auto

Codec Preset - if specified, some properties below ignored

profile

option_fixed

Auto

Codec Profile

level

option_fixed

Auto

Sets the level flag in the output bitstream

maxrate

int

0

The maximum bit rate in bps is the peak bit rate used for VBR rate control

size

string

Resolution of video. Format: WIDTHxHEIGHT.

ar

option

Aspect ratio of video.

ar_type

option_fixed

Type of video's aspect ratio.

bufsize

int

0

Specifies the VBV(HRD) buffer size. in bits. Set 0 to use the default VBV buffer size

initialdelay

int

0

Specifies the VBV(HRD) initial delay in bits. Set 0 to use the default VBV initial delay

enableAQ

option_fixed

true

Set this to TRUE to enable adaptive quantization

intraRefreshPeriod

int

0

Specifies the interval between successive intra refresh if intraRefreshCount is set

intraRefreshCount

int

0

Specifies the length of intra refresh in number of frames for periodic intra refresh. This value should be smaller than intraRefreshPeriod

disable_cabac

option_fixed

false

Enable or disable CABAC

mvprecision

option_fixed

Auto

Specifies the desired motion vector prediction precision

disable_sps_pps

option_fixed

false

Disable writing of Sequence and Picture parameter for every IDR frame

separateColourPlaneFlag

option_fixed

false

Set 'true' to enable 4:4:4 separate colour planes

deblock

option_fixed

1

Specifies the deblocking filter mode

enableTemporalSVC

option_fixed

false

Set to 'true' to enable SVC temporal

hierarchicalPFrames

option_fixed

false

Set to 'true' to enable hierarchical PFrames

hierarchicalBFrames

option_fixed

false

Set to 'true' to enable hierarchical BFrames

outputBufferingPeriodSEI

option_fixed

true

Set 'true' to write SEI buffering period syntax in the bitstream

outputPictureTimingSEI

option_fixed

true

Set 'true' to write SEI picture timing syntax in the bitstream

outputFramePackingSEI

option_fixed

true

Set 'true' to enable writing of frame packing arrangement SEI messages to bitstream

outputRecoveryPointSEI

option_fixed

true

Set'true' to enable writing of recovery point SEI message

numTemporalLayers

int

Specifies max temporal layers to be used for hierarchical coding. Valid value range is [1,10]

outputAUD

option_fixed

true

Set 'true' to write Access Unit Delimiter syntax.

maxNumRefFrames

int

Specifies the DPB size used for encoding. Setting it to 0 will let driver use the default dpb size. The low latency application which wants to invalidate reference frame as an error resilience tool is recommended to use a large DPB size so that the encoder can keep old reference frames which can be used if recent

ltrNumFrames

int

Specifies the maximum number of long term references can be used for prediction

ltrTrustMode

option_fixed

Specifies the LTR operating mode. Set to 'false' to disallow encoding using LTR frames until later specified. Set to 'true' to allow encoding using LTR frames unless later invalidated.

enableConstrainedEncoding

option_fixed

Set this to 1 to enable constrainedFrame encoding where each slice in the constarined picture is independent of other slices.

adaptiveTransformMode

option_fixed

Enable the AdaptiveTransform Mode.

fmoMode

option_fixed

Enable the FMO Mode.

interlace

option_fixed

Auto

Interlace type

NVIDIA NVEnc H.264 Lossless Encoder

Configuration Parameter: l264

Additional attributes

Name

Type

Default

Description

preset

option_fixed

lossless

Codec Preset

size

string

Resolution of video. Format: WIDTHxHEIGHT.

ar

option

Aspect ratio of video.

ar_type

option_fixed

Type of video's aspect ratio.

disable_sps_pps

option_fixed

false

Disable writing of Sequence and Picture parameter for every IDR frame

outputBufferingPeriodSEI

option_fixed

true

Set 'true' to write SEI buffering period syntax in the bitstream

outputPictureTimingSEI

option_fixed

true

Set 'true' to write SEI picture timing syntax in the bitstream

outputFramePackingSEI

option_fixed

true

Set 'true' to enable writing of frame packing arrangement SEI messages to bitstream

outputRecoveryPointSEI

option_fixed

true

Set'true' to enable writing of recovery point SEI message

outputAUD

option_fixed

true

Set 'true' to write Access Unit Delimiter syntax.

NVIDIA NVEnc H.265 (HEVC) Encoder

Configuration Parameter: n265

Additional attributes

Name

Type

Default

Description

b

int

5M

The average bit rate in bps is the target bit rate used for rate control

g

int

15

This is the IDR period

bf

int

1

This sets the distance of one P picture from the previous P picture. e.g. for IBBPBBP, set the value as 3

rc_type

option_fixed

Auto

The rate control type

preset

option_fixed

Auto

Codec Preset - if specified, some properties below ignored

level

option_fixed

Auto

Specifies the level of the encoded bitstream.

tier

option_fixed

Main

maxrate

int

0

The maximum bit rate in bps is the peak bit rate used for VBR rate control

size

string

Resolution of video. Format: WIDTHxHEIGHT.

ar

option

Aspect ratio of video.

ar_type

option_fixed

Type of video's aspect ratio.

bufsize

int

0

Specifies the VBV(HRD) buffer size. in bits. Set 0 to use the default VBV buffer size

initialdelay

int

0

Specifies the VBV(HRD) initial delay in bits. Set 0 to use the default VBV initial delay

enableAQ

option_fixed

true

Set this to TRUE to enable adaptive quantization

intraRefreshPeriod

int

0

Specifies the interval between successive intra refresh if intraRefreshCount is set

intraRefreshCount

int

0

Specifies the length of intra refresh in number of frames for periodic intra refresh. This value should be smaller than intraRefreshPeriod

mvprecision

option_fixed

Auto

Specifies the desired motion vector prediction precision

disable_sps_pps

option_fixed

false

Disable writing of Sequence and Picture parameter for every IDR frame

deblock

option_fixed

true

Set 'true' to enable in loop filtering across slice boundary.

useConstrainedIntraPred

option_fixed

Set 'true' to enable constrained intra prediction.

outputBufferingPeriodSEI

option_fixed

true

Set 'true' to write SEI buffering period syntax in the bitstream

outputPictureTimingSEI

option_fixed

true

Set 'true' to write SEI picture timing syntax in the bitstream

outputAUD

option_fixed

true

Set 'true' to write Access Unit Delimiter syntax.

enableLTR

option_fixed

Set 'true' to enable use of long term reference pictures for inter prediction.

maxNumRefFramesInDPB

int

Specifies the maximum number of references frames in the DPB.

ltrNumFrames

int

Specifies the maximum number of long term references can be used for prediction

maxTemporalLayersMinus1

int

Specifies the max temporal layer used for hierarchical coding.

CUDA H.264 Video Encoder

Configuration Parameter: c264

Additional attributes

Name

Type

Default

Description

b

int

6000000

The average bit rate in bps is the target bit rate used for VBR rate control

maxrate

int

6200000

The maximum bit rate in bps is the peak bit rate used for VBR rate control

preset

option

Custom

Set the encoding parameters according to the presets required for supported encoding targets

size

string

Resolution of video. Format: WIDTHxHEIGHT.

g

int

15

This is the IDR period for H264

bf

int

1

This sets the distance of one P picture from the previous P picture. e.g. for IBBPBBP, set the value as 3

Threads. The number of threads to use while processing. Adjust this to match how many of your available CPU cores you want to use.

slices

option_fixed

4

Slices. Each frame is split into this number of slices. This affects multithreading performance, as well as filesize: Increasing the number of slices might speed up performance, but also increases the filesize.

slicecrc

option_fixed

0

Error correction/detection. 0=off, 1=on. Enabling this option adds CRC information to each slice. This makes it possible for a decoder to detect errors in the bitstream, rather than blindly decoding a broken slice.

partitions - The frame partitions are independently decodable by the bool decoder, meaning that partitions can be decoded even though earlier partitions have been lost. Note that intra predicition is still done over the partition boundary.

speed

int

3

Encoding speed

crf

int

0

Select the quality for constant quality mode

AMD AMF H.264 Encoder

Configuration Parameter: h264_amf

Additional attributes

Name

Type

Default

Description

b

int

5M

The average bit rate in bps is the target bit rate used for VBR rate control

g

int

15

Group of picture (GOP) size

maxrate

int

0

Set max bitrate tolerance (in bits/s). Requires bufsize to be set

minrate

int

0

Set min bitrate tolerance (in bits/s). Most useful in setting up a CBR encode. It is of little use elsewise

bufsize

int

0

Set ratecontrol buffer size (in bits). Depends on the profile level of the video being encoded. Set only if you're encoding for a hardware device.

bf

int

0

This sets the distance of one P picture from the previous P picture. e.g. for IBBPBBP, set the value as 3

usage

option_fixed

transcoding

Encoder Usage

profile

option_fixed

main

Profile

level

option_fixed

auto

Profile Level

quality

option_fixed

speed

Quality Preference

rc

option_fixed

cqp

Rate Control Method

enforce_hrd

bool

false

Enforce HRD

filler_data

bool

false

Filler Data Enable

vbaq

bool

false

Enable VBAQ

frame_skipping

bool

false

Rate Control Based Frame Skip

qp_i

int

-1

Quantization Parameter for I-Frame

qp_p

int

-1

Quantization Parameter for P-Frame

qp_b

int

-1

Quantization Parameter for B-Frame

preanalysis

bool

false

Pre-Analysis Mode

max_au_size

int

0

Maximum Access Unit Size for rate control (in bits)

header_spacing

int

-1

Header Insertion Spacing

bf_delta_qp

int

4

B-Picture Delta QP

bf_ref

bool

true

Enable Reference to B-Frames

bf_ref_delta_qp

int

4

Reference B-Picture Delta QP

intra_refresh_mb

int

0

Intra Refresh MBs Number Per Slot in Macroblocks

coder

option_fixed

auto

Coding Type

me_half_pel

bool

true

Enable ME Half Pixel

me_quarter_pel

bool

true

Enable ME Quarter Pixel

aud

bool

false

Inserts AU Delimiter NAL unit

AMD AMF H.265 (HEVC) Encoder

Configuration Parameter: hevc_amf

Additional attributes

Name

Type

Default

Description

b

int

5M

The average bit rate in bps is the target bit rate used for VBR rate control

g

int

15

Group of picture (GOP) size

maxrate

int

0

Set max bitrate tolerance (in bits/s). Requires bufsize to be set

minrate

int

0

Set min bitrate tolerance (in bits/s). Most useful in setting up a CBR encode. It is of little use elsewise

bufsize

int

0

Set ratecontrol buffer size (in bits). Depends on the profile level of the video being encoded. Set only if you're encoding for a hardware device.

bf

int

1

This sets the distance of one P picture from the previous P picture. e.g. for IBBPBBP, set the value as 3

usage

option_fixed

transcoding

Encoder Usage

profile

option_fixed

main

Profile

profile_tier

option_fixed

main

Profile tier

level

option_fixed

auto

Profile Level

quality

option_fixed

balanced

Quality Preference

rc

option_fixed

cqp

Rate Control Method

header_insertion_mode

option_fixed

none

Header insertion mode

gops_per_idr

int

60

GOPs per IDR 0-no IDR will be inserted

preanalysis

bool

false

Pre-Analysis Mode

vbaq

bool

false

Enable VBAQ

enforce_hrd

bool

false

Enforce HRD

filler_data

bool

false

Filler Data Enable

max_au_size

int

0

Maximum Access Unit Size for rate control (in bits)

min_qp_i

int

-1

Min quantization parameter for I-frame

max_qp_i

int

-1

Max quantization parameter for I-frame

min_qp_p

int

-1

Min quantization parameter for P-frame

max_qp_p

int

-1

Max quantization parameter for P-frame

qp_p

int

-1

Quantization parameter for P-frame

qp_i

int

-1

Quantization parameter for I-frame

skip_frame

bool

false

Rate Control Based Frame Skip

me_half_pel

bool

true

Enable ME Half Pixel

me_quarter_pel

bool

true

Enable ME Quarter Pixel

aud

bool

false

Inserts AU Delimiter NAL unit

libvpx VP9

Configuration Parameter: libvpx-vp9

Additional attributes

Name

Type

Default

Description

auto-alt-ref

int

-1

Enable use of alternate reference frames (2-pass only)

lag-in-frames

int

25

Number of frames to look ahead for alternate reference frame selection

arnr-maxframes

int

0

altref noise reduction max frame count

arnr-strength

int

3

altref noise reduction filter strength

arnr-type

option

centered

altref noise reduction filter type

arnr_type

int

3

altref noise reduction filter type

tune

option

Tune the encoding to a specific scenario

deadline

option

good

Time to spend encoding, in microseconds.

quality

int

1000000

error-resilient

flags

Error resilience configuration

max-intra-rate

int

-1

Maximum I-frame bitrate (pct) 0=unlimited

er

partitions - The frame partitions are independently decodable by the bool decoder, meaning that partitions can be decoded even though earlier partitions have been lost. Note that intra predicition is still done over the partition boundary.

crf

int

-1

Select the quality for constant quality mode

static-thresh

int

0

A change threshold on blocks below which they will be skipped by the encoder

drop-threshold

int

0

Frame drop threshold

noise-sensitivity

int

0

Noise sensitivity

undershoot-pct

int

-1

Datarate undershoot (min) target (%)

overshoot-pct

int

-1

Datarate overshoot (max) target (%)

cpu-used

int

1

Quality/Speed ratio modifier

lossless

int

-1

Lossless mode

tile-columns

int

-1

Number of tile columns to use, log2

tile-rows

int

-1

Number of tile rows to use, log2

frame-parallel

Enable frame parallel decodability features

aq-mode

option

adaptive quantization mode

aq_mode

variance - Variance based Aq

complexity - Complexity based Aq

cyclic - Cyclic Refresh Aq

equator360 - 360 video Aq

level

double

-1.000000

Specify level

row-mt

Row based multi-threading

tune-content

option

Tune content type

tune_content

screen - Screen capture content

film - Film content; improves grain retention

corpus-complexity

int

-1

corpus vbr complexity midpoint

speed

int

1

vp8flags

flags

flags

altref - enable use of alternate reference frames (VP8/2-pass only)

arnr_max_frames

int

0

altref noise reduction max frame count

arnr_strength

int

3

altref noise reduction filter strength

rc_lookahead

int

25

Number of frames to look ahead for alternate reference frame selection